1. Edit your runlevels. As root, edit (with your favorite text editor) /etc/inittab to use runlevel 3 instead of 4 or 5 (not sure which Suse uses). Any way it should look like this:
2. type startx
3. in KDE, hit the K (equivalent to windows Start button), select quit or logout or whatever
EDIT: #3 will work after you've done #1 as it will kill X and bring you back to your default runlevel, which will be multi-user command line.
Hope this helps.